[The disappearance of the dependence of actin-myosin interaction on the phosphorylation of myosin light chains in the "freezing" of the structure of heavy meromyosin by a bifunctional reagent].
Using glycerinated muscle fibers, free of myosin, tropomyosin and troponin, a study was made of the structural state of F-actin modified by N-(iodoacetyl)-N'-(1-naphthyl-5-sulfo)-ethylendiamine (1.5-IAEDANS) and by rhodaminyl--phalloin at decoration of thin filaments with a proteolytic fragment of myosin--heavy meromyosin containing phosphorylated and dephosphorylated myosin light chains. The heavy meromyosin used has three SH-groups of heavy chain SH1, SH2 and SH chi modified by bifunctional reagent N,N'-n-phenylmaleimide (SH1-SH2, SH2-SH chi). At decoration of thin filaments with heavy meromyosin, some changes in polarized fluorescence of rhodaminyl--phalloin and 1.5-IAEDANS independent of phosphorylation of myosin light chains were found. Fluorescence anisotropy of the fiber was found to depend primarily on the character of heavy chain of SH-group modification. The ability of heavy chains to change their conformations is supposed to play an important role in the mechanism of myosin system modulation of muscle contraction.
Borovikov
Iu S
IuS
Szczesna
D
D
Khoroshev
M I
MI
Kakol
I
I
D000199:Actins / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D003592:Cytophotometry / Q000295:instrumentation / Q000379:methods; D004347:Drug Interactions; D005454:Fluorescence Polarization; D066298:In Vitro Techniques; D008301:Maleimides / Q000494:pharmacology; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D015879:Myosin Subfragments / Q000187:drug effects* / Q000378:metabolism; D009218:Myosins / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D011817:Rabbits
D000199:Actins; D003432:Cross-Linking Reagents; D008301:Maleimides; D015879:Myosin Subfragments; C028525:N-phenylmaleimide; D009218:Myosins
Ischeznovenie zavisimosti aktin-miozinovogo vzaimodeĭstviia ot fosforilirovaniia legkikh tsepeĭ miozina pri "zamorazhivaniia" struktury tiazhelogo meromiozina bifunktsional'nym reagentom.